1. Technical Field of the Invention
The present invention relates to a color filter substrate, a method of manufacturing a color filter substrate, an electro-optical device, a method of manufacturing an electro-optical device, and an electronic apparatus, and more specifically, the present invention relates to a technique adapted for a liquid crystal display having a structure in which the thickness of the liquid crystal layers is different from each other in the two areas of a single pixel.
2. Description of the Related Art
Generally, liquid crystal displays have been used as display means in electronic apparatuses such as cellular phones, portable information terminals such as PDAs, personal computers, etc. Recently, PDPs (plasma display panels) have also been used in television devices, etc., and moreover, organic electroluminescent devices have been recently used in some apparatuses. Various types of such electro-optical devices using the electro-optical effect of different electro-optical materials are expected to be used in more and more fields in the future.
A transmissive liquid crystal panel which is provided with an illuminator such as a backlight at the rear thereof and enables viewing of a display by making use of the light of this illuminator has been used because a conventional liquid crystal display has no self-luminescent performance. In case of using an illuminator, however, since it is difficult to reduce power consumption and especially it has an effect on the life span of a battery for portable apparatuses, a reflective liquid crystal panel, which does not require an illuminator, has been widely used.
Meanwhile, as the precision of a display becomes higher and higher or a display becomes more colorful, a situation has occurred that the brightness of a display lacks in a reflective liquid crystal panel, so that a transflective liquid crystal panel has been developed, which can provide a reflective display while using a backlight. It has been known that as this transflective liquid crystal panel, each pixel disposed in the display region comprises a light transmission portion configured to enable light to be transmitted and a light reflection portion configured to enable light to be reflected by disposing a light reflection layer, wherein the light transmission portion is usually configured by providing an opening in the light reflection.
However, a problem occurs wherein if a color filter is provided in the transflective liquid crystal panel to enable colors to be displayed, it is difficult to control the color adjustment between the transmissive display using the light transmission portion within each pixel and the reflective display using the light reflection portion within each pixel. Such problems occur because light passing through the colored layer of a color filter passes only once in the transmissive display since the light irradiated from a backlight is transmitted through a liquid crystal panel and is emitted toward an observing side; however, light passing through the colored layer of a color filter passes twice in the reflective display since the external light incident from an observing side is reflected by a light reflection layer and emitted toward the observing side. That is, if hue or brightness of a colored layer of a color filter is adjusted to favor the transmissive display, chromaticness can be attained but a display becomes dark in a reflective display, and on the contrary, if hue or brightness of a colored layer of a color filter is adjusted to favor the reflective display, the chromaticness required in a transmissive display cannot be attained.
Meanwhile, as illustrated in FIG. 5(a) to 5(c) of the document, the difference between the transmissive display and the reflective display in a color display condition is reduced by forming an opening of a light reflection film corresponding to the largest film thickness portion of a colored pixel.
However, in the above-mentioned method, it is difficult to sufficiently control display colors of a transmissive display and a reflective display since it is difficult to sufficiently obtain the difference in the film thickness of a colored layer between a portion used in a transmissive display and a portion used in a reflective display. On this account, as illustrated in FIG. 10, a liquid crystal display 100 has been devised wherein two types of colored layers are arranged in every pixel, a colored layer 114C of a dark color with a thick optical film thickness is arranged to overlap an opening 113a of a light reflection layer 113, and a colored layer 114F of a light color with a thin optical film thickness is arranged to overlap a light reflection layer 113.
In the liquid crystal display 100, on one side of a substrate 110, a transparent base layer 112 is formed on a base member 111, and a light reflection layer 113 made of aluminum is formed on the base layer 112. An opening 113a is provided in the light reflection layer 113, as described above. A color filter is configured such that a colored layer 114C is disposed on the corresponding opening 113a and a colored layer 114F is disposed on the light reflection layer 113. Also, a light shielding portion 114B is for preventing a light leak of a region between pixels. A transparent protective film 115 is formed on a color filter, and a transparent electrode 116 made of ITO (indium tin oxide), etc. is formed on the protective film 115. An alignment film 117 is formed on the transparent electrode 116. Also, on the other side of the substrate 120, a transparent electrode 122 similar to the above transparent electrode is formed on a base member 121 and an alignment film 123 is formed on the transparent electrode 122.
By the above-mentioned configuration, in a light transmission portion Pt performing a transmissive display and a light reflection portion Pr performing a reflective display within a pixel P, the color design is implemented separately thereby making it possible to improve a display quality in both displays and to reduce the difference between both displays in the aspect of a color display.
Moreover, in the above-mentioned liquid crystal display 100, in order to reduce the difference in a substantial retardation value of a liquid crystal layer LC between a transmissive display and a reflective display, and to improve the balance of both displays to elevate the display quality, a liquid crystal layer LC is configured to be made thick in a light transmission portion Pt where an opening 113a is provided and a liquid crystal layer LC is configured to be made thin in a light reflection portion Pr where a light reflection layer 113 is disposed within a pixel P. Specifically, by forming the above-mentioned protective film 115 only in the region other than a light transmission portion Pt, i.e., only the region including a light reflection portion Pr, a surface of the substrate 110 is configured to be low in a light transmission portion Pt and is configured to be high in a light reflection portion Pr.
Meanwhile, in the above-mentioned liquid crystal display 100, within a single pixel P, it is necessary to dispose a colored layer 114C and a colored layer 114F adjacent to each other, and a colored layer 114C and a colored layer 114F are formed to overlap each other so as not to have a gap at an interface portion between both colored layers. In this case, a problem occurs wherein a display quality is deteriorated in the vicinity of the corresponding surface and especially the display quality of a transmissive display is deteriorated, since a protrusion 114E is formed on the surface of a color filter due to overlapping of both colored layers, and a protrusion or a recessed portion is formed in the vicinity of the surface of a substrate 110 in contact with a liquid crystal layer LC due to the protrusion 114E. Also, a problem occurs wherein since a partial tear or omission tends to occur in a transparent electrode 116 on the interface portion due to surface unevenness by the above-mentioned protrusion 114E, the state of electric field application changes in a light transmission portion Pt, which also deteriorates the display quality of a transmissive display.
Therefore, the present invention is directed to overcoming these problems, and an object of the present invention is to provide technical means in a color filter substrate or an electro-optical device for preventing optical and electrical defects in the interface portion where different colored layers are adjacent to each other, and for preventing the occurrence of bad quality.